下扬子地区上二叠统龙潭组致密砂岩储层油气显示较为丰富，且在近年来已中取得了初步工业油流，但尚未获得重大勘探进展。为全面分析下扬子地区龙潭组致密砂岩储层发育特征并进一步探讨其优质储层形成机制，采用岩心观察、铸体薄片、X射线衍射、阴极发光、扫描电镜、能谱分析、核磁共振、成像测井以及流体包裹体分析等实验手段，对龙潭组砂岩岩矿组成、成岩作用和储层特征进行了系统研究。结果表明，下扬子地区龙潭组致密砂岩储层主要包括压实作用、胶结作用和溶蚀作用等成岩作用类型，压实作用和胶结作用导致储层致密化，而溶蚀作用是主要的建设性成岩作用，受成岩酸性和碱性环境交替变化而使储层受长石溶蚀和石英溶蚀的叠加影响，成岩演化序列总体处于中成岩阶段；储层孔隙以纳米级孔隙发育为主，孔隙类型以次生粒内孔隙和微裂缝为主，而原生粒间孔隙较不发育；古油藏稀油沥青充填特征和流体包裹体显微特征表明，龙潭组存在较大规模的多期油气充注和成藏过程。下扬子陆域黄桥地区和南黄海盆地崂山隆起大致处于构造相对稳定区，龙潭组致密砂岩储层溶蚀增孔作用较其他地区更为显著，呈现出相对较好的勘探前景。

The Upper Permian Longtan Formation in the Lower Yangtze Area is rich in oil and gas. Preliminary industrial oil flows have been obtained in recent years, although significant exploration progress remains elusive. In order to provide a comprehensive analysis of the development characteristics of the Longtan tight sandstone reservoirs in the Lower Yangtze Area and to explore the formation mechanisms of high-quality reservoirs. A systematic investigation of the mineral composition, diagenesis, and reservoir characteristics of the Longtan sandstones was conducted using various experimental methods, including core observation, thin-section analysis, X-ray diffraction, cathodoluminescence, scanning electron microscopy, energy-dispersive spectroscopy, nuclear magnetic resonance, imaging logging, and fluid inclusion analysis. The results indicate that the tight sandstone reservoirs are primarily shaped by diagenetic processes such as compaction, cementation, and dissolution. Compaction and cementation contributed to reservoir densification, while dissolution was the principal constructive diagenetic process. Alternating acidic and alkaline diagenetic environments promoted the dissolution of feldspar and quartz, leading to cumulative effects on the reservoirs. The overall diagenetic evolution occurred during the mesogenetic stage. Reservoir porosity was predominantly developed at the nanoscale, with secondary intragranular pores and microfractures being the dominant pore types, whereas primary intergranular pores were less developed. The characteristics of paleo-reservoirs filled with light oil bitumen and the microscopic features of fluid inclusions, suggest substantial multiepisode hydrocarbon charging and accumulation processes in the Longtan Formation. The Huangqiao onshore region of the Lower Yangtze Area and the Laoshan Uplift in the South Yellow Sea Basin, both located in relatively tectonically stable regions, exhibit more pronounced dissolution-enhanced porosity in the Longtan Formation tight sandstones than in other areas, indicating promising exploration potential.